Price unit not allowed since valuation price would be zero

What causes this issue?

You have changed the price unit of the material. As a result, the
valuation price (moving average price or standard price) has to be
redetermined. However, with the price unit you have entered, the new
valuation price would be zero. The price unit entered is therefore not
allowed.

System Response

The way the system responds depends on how this message has been
configured in your system:
If it appears as a warning, the system replaces your entry with the old
entry.
If it appears as an error message, the system does not replace your
entry, but you must correct it.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

In Customizing for the <LS>Material Master</>, you can define whether
this message is to appear as a warning or as an error message.
You do this in the activity
<DS:SIMG.SIMG_CFMENUOLMSOMT4>Define attributes of system messages</>.

Error message extract from SAP system. Copyright SAP SE.